Which test is historically recognized for evaluating organic material in wastewater?

The BOD (Biochemical Oxygen Demand) test is historically recognized for evaluating organic material in wastewater because it specifically measures the amount of dissolved oxygen that microorganisms will consume while decomposing organic matter over a specified period, typically five days at a controlled temperature. This test helps quantify the level of biodegradable organic material present in the water, making it a crucial indicator of water pollution and the potential impact that discharges may have on receiving waters.

BOD is significant in wastewater treatment processes as it provides insight into the effectiveness of treatment methods and the organic loading that a treatment plant might experience. A high BOD indicates a large amount of organic waste, which can lead to oxygen depletion in natural water bodies if not adequately treated, hence posing a threat to aquatic life.

Other tests mentioned, like COD (Chemical Oxygen Demand), while also relevant for measuring organic and inorganic pollutants, assess the total oxygen demand from all compounds and are not solely indicative of biodegradable material. SVI (Sludge Volume Index) pertains to the settling properties of activated sludge and does not measure organic load directly, while TSS (Total Suspended Solids) measures the concentration of suspended solids without providing information specifically about organic content. Thus, the BOD test remains the primary historical method for evaluating organic